I modded my Crybaby Wah pedal a little. I replaced 1 resistor and another with a linear 100k pot. I hadn't used it for a while and then the sound randomly went distorted and adjusting the pot increased/decreased how much distortion there was. Rocking the foot backwards and forwards did nothing!

So I took the 100k pot out and put the original 33k resistor back in place to see if that was the problem, but it is still distorted!

Are there any electrical gurus out there who have any idea why I'd be getting a distorted sound and no response from rocking the foot?

Thanks a lot.
Ok, I've been messing around some more and it seems my problem was due to dodgy soldering. That'll teach me to buy a cheap soldering iron!